#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System.Text;
using System.Linq;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
using System.Collections.Generic;
using HeuristicLab.Problems.DataAnalysis.Symbolic.Symbols;
using System;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.Symbols;

namespace HeuristicLab.Problems.DataAnalysis.Views.Symbolic {
  public class SymbolicExpressionTreeLatexFormatter {
    public SymbolicExpressionTreeLatexFormatter()
      : base() { }

    public string Format(SymbolicExpressionTree symbolicExpressionTree) {
      try {
        StringBuilder strBuilder = new StringBuilder();
        strBuilder.AppendLine("\\begin{eqnarray}");
        strBuilder.AppendLine(FormatRecursively(symbolicExpressionTree.Root));
        strBuilder.AppendLine("\\end{eqnarray}");
        return strBuilder.ToString();
      }
      catch (NotImplementedException ex) {
        return ex.Message + Environment.NewLine + ex.StackTrace;
      }
    }

    private string FormatRecursively(SymbolicExpressionTreeNode node) {
      StringBuilder strBuilder = new StringBuilder();

      FormatBegin(node, strBuilder);

      if (node.SubTrees.Count > 0) {
        strBuilder.Append(FormatRecursively(node.SubTrees[0]));
      }
      foreach (SymbolicExpressionTreeNode subTree in node.SubTrees.Skip(1)) {
        FormatSep(node, strBuilder);
        // format the whole subtree
        strBuilder.Append(FormatRecursively(subTree));
      }

      FormatEnd(node, strBuilder);

      return strBuilder.ToString();
    }

    private void FormatBegin(SymbolicExpressionTreeNode node, StringBuilder strBuilder) {
      if (node.Symbol is Addition) {
        strBuilder.Append(@" \left( ");
      } else if (node.Symbol is Subtraction) {
        strBuilder.Append(@" \left( ");
      } else if (node.Symbol is Multiplication) {
      } else if (node.Symbol is Division) {
        if (node.SubTrees.Count != 2) throw new NotImplementedException("Division with more than 2 arguments is not implemented.");
        strBuilder.Append(@" \frac{ ");
      } else if (node.Symbol is Constant) {
        strBuilder.Append(" c ");
      } else if (node.Symbol is Variable) {
        var varNode = node as VariableTreeNode;
        strBuilder.Append(" " + varNode.ToString()+ " ");
      } else if (node.Symbol is ProgramRootSymbol) {
      } else if (node.Symbol is Defun) {
        var defunNode = node as DefunTreeNode;
        strBuilder.Append(defunNode.FunctionName + " & = & ");
      } else if (node.Symbol is InvokeFunction) {
        var invokeNode = node as InvokeFunctionTreeNode;
        strBuilder.Append(invokeNode.Symbol.FunctionName + @" \left( ");
      } else if (node.Symbol is StartSymbol) {
        strBuilder.Append("Result & = & ");
      } else if(node.Symbol is Argument) {
        var argSym = node.Symbol as Argument;
        strBuilder.Append(" ARG+"+argSym.ArgumentIndex+" ");
      } else {
        throw new NotImplementedException("Export of " + node.Symbol + " is not implemented.");
      }
    }

    private void FormatSep(SymbolicExpressionTreeNode node, StringBuilder strBuilder) {
      if (node.Symbol is Addition) {
        strBuilder.Append(" + ");
      } else if (node.Symbol is Subtraction) {
        strBuilder.Append(" - ");
      } else if (node.Symbol is Multiplication) {
      } else if (node.Symbol is Division) {
        strBuilder.Append(" }{ ");
      } else if (node.Symbol is ProgramRootSymbol) {
        strBuilder.Append(@"\\" + Environment.NewLine);
      } else if (node.Symbol is Defun) {
      } else if (node.Symbol is InvokeFunction) {
        strBuilder.Append(" , ");
      } else if (node.Symbol is StartSymbol) {
        strBuilder.Append(@"\\" + Environment.NewLine + " & & ");
      } else {
        throw new NotImplementedException("Export of " + node.Symbol + " is not implemented.");
      }
    }

    private void FormatEnd(SymbolicExpressionTreeNode node, StringBuilder strBuilder) {
      if (node.Symbol is Addition) {
        strBuilder.Append(@" \right) ");
      } else if (node.Symbol is Subtraction) {
        strBuilder.Append(@" \right) ");
      } else if (node.Symbol is Multiplication) {
      } else if (node.Symbol is Division) {
        strBuilder.Append(" } ");
      } else if (node.Symbol is Constant) {
      } else if (node.Symbol is Variable) {
      } else if (node.Symbol is ProgramRootSymbol) {
      } else if (node.Symbol is Defun) {
      } else if (node.Symbol is InvokeFunction) {
        strBuilder.Append(@" \right) ");
      } else if (node.Symbol is StartSymbol) {
      } else if (node.Symbol is Argument) {
      } else {
        throw new NotImplementedException("Export of " + node.Symbol + " is not implemented.");
      }
    }
  }
}